1. Field of the Invention
The present invention relates to toys. In particular, the present invention relates to toys in the form of helices, springs, and coils having variable rates of movement.
2. Description of the Related Art
A helix is generally a shape such as a spring or coil, for example. A helix may be mathematically defined as a space curve having parametric equations according to the following: x=r cos t; y=r sin t; z=ct (where 0≦t<2π; r is the radius of the helix; 2πc is a constant giving the vertical separation of the helix's loops).
Toy helices are well-known, such as a toy called a Slinky®, for example. Such toy helices are formed as a coil with material having a uniform thickness, width, and elasticity. When a toy helix is positioned to effect movement of the helix, for example, when descending from a first stair surface to a second stair surface, the toy helix generally moves, i.e., stretches and compresses, at a constant speed during movement. When moving from the first stair surface to the second stair surface, the toy helix stretches and compresses to walk down the stairs. Further, when a toy helix is stretched, the toy helix returns to an original, compressed shape at a generally constant rate of movement. The constant rate of movement results from the toy helices, such as springs and coils, typically being constructed from a single type of material having a uniform thickness, width, and elasticity. The elasticity of a material is generally the material property which causes the material to be restored to an initial or original shape after stretching or compression.